Perhaps you should try some spelling variations:
sach tu » sach thu, cach tu, sach ty
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
cac duc » cac du, cao duc, cac nuoc
cac dac » cac dan, cac dai, cac bac
va hanh » van hanh, va thanh, va danh
hanh da » hanh dao, hanh dua, hanh va
sac ky » cac ky, sai ky
da su » dan su, dat su, va su
kien » bien, vien, tien

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: tu ((sach tu) or (sac ky)) nang xa hoi. hieu va ((cac duc) or (cac dac)) va hanh da su kien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach tu) OR (sac ky)) nang xa hoi. hieu va ((cac duc) OR (cac dac)) va hanh da su kien.
• Adding a wildcard symbol may retrieve word variants: tu ((sach tu) or (sac ky)) nang xa hoi. hieu va ((cac duc) or (cac dac)) va hanh da su kien*.